1. Field of the Invention
The present invention relates to a catalyst for use in the production of a gas containing methane as the main component by catalytic reaction of a hydrocarbon having 2 to 12 carbon atoms with steam. More particularly, the present invention relates to an improved ternary catalyst comprising nickel and/or cobalt, lanthanum and/or cerium and aluminum.
2. Description of the Prior Art
A gas containing methane as the main component is important as an energy source causing no pollution and is valuable as a fuel gas or city gas. In addition to natural gas, there is known substitute natural gas (hereinafter referred to as "SNG") which contains methane as the main component. A most popular process commercially adopted for the production of SNG is a so-called low-temperature steam-reforming process which comprises catalytically reacting a light petroleum distillate (naphtha composed mainly of paraffinic hydrocarbons) with steam at a relatively low temperature. As typical instances of this reforming process, there can be mentioned a CRG process (catalytic rich gas process) of British Gas Corporation (cf. U.S. Pat. Nos. 3,415,634 and 3,420,642), an MRG process (methane rich gas process) of Japan Gasoline Co. (cf. U.S. Pat. No. 3,429,680) and a Gasynthan process of BASF-LURGI (cf. Japanese Patent Application Laid-Open Specifications No. 52801/74 and No. 52802/74).
In these low-temperature steam-reforming processes, a hydrocarbon is reacted with steam at 300.degree. to 550.degree. C. in the presence of a nickel catalyst. As the nickel catalyst, there can be mentioned a nickel-alumina catalyst, a nickel-silica catalyst, a nickel-magnesia catalyst, a catalyst formed by incorporating Cu, Cr and Mn into nickel-alumina and a catalyst formed by incorporating La and Ce as promoters into nickel-alumina. Among these catalysts, nickel-alumina catalysts are used most frequently.
Nickel-alumina catalysts take a form of NiO-Al.sub.2 O.sub.3 when prepared, but the form is converted to Ni-Al.sub.2 O.sub.3 prior to the reaction because NiO is reduced to Ni in a reactor. The activity and durability of the catalysts generally depends on the preparation conditions and methods, and it is usually difficult to produce a catalyst with high activity consistently.